The Ensatina salamander has been extensively investigated because it is a ring species — a species that demonstrates how geography and the gradual accumulation of genetic differences factor into the process of speciation. Biologist Tom Devitt continues the more than 50 years of Ensatina research by applying new genetic techniques and asking new questions about this classic evolutionary example.
UC Museum of Paleontology
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Correspondence to the Next Generation Science Standards is indicated in parentheses after each relevant concept. See our conceptual framework for details.
- Speciation is the splitting of one ancestral lineage into two or more descendent lineages.
- Speciation requires reproductive isolation.
- A hallmark of science is exposing ideas to testing. (P3, P4, P6, P7)
- Scientists test their ideas using multiple lines of evidence. (P6, NOS2)
- Scientists can test ideas about events and processes long past, very distant, and not directly observable.
- Scientific knowledge is open to question and revision as we come up with new ideas and discover new evidence. (P4, P6, NOS3)
- The real process of science is complex, iterative, and can take many different paths.
- Scientists use multiple research methods (experiments, observational research, comparative research, and modeling) to collect data. (P2, P3, P4, NOS1)
- Science is a human endeavor. (NOS7)
- Scientists use the similarity of DNA nucleotide sequences to infer the relatedness of taxa. (LS4.A)
- Scientists use anatomical evidence to infer the relatedness of taxa. (LS4.A)
- Scientists use the geographic distribution of fossils and living things to learn about the history of life.
- Scientists use experimental evidence to study evolutionary processes.
- Speciation is often the result of geographic isolation.